All WASR series rifles, regardless of caliber, are imported as single stack receivered guns. As such, the WASR receiver does not have the mag well area 'dimples' that are found on the SAR receiver. Once the WASR receivers are machined to take regular AK mags, the lack of the two 'dimples' is the main difference between a WASR-3 and an SAR-3.
Until the rifles are in the dealers' and consumers' hands for examination, we will not know if there are other significant differences to note.
I will put the underfolder stock on myself. I am really looking forward to getting the weapon. I saw some WASR 1s at the shows this past weekend. In my humble opinion, they are considerably better in quality than their SAR counterparts. The furnature is that same wood used on the AMD 63s that came from Centerfire. They looked so nice I was tempted to buy one. Jack